ql:quickload is the Quicklisp command to download and install a library that is part of Quicklisp. Create an Issue for quicklisp-projects on Github to request inclusion of a new project in Quicklisp. The inclusion policy is quite inclusive. Perhaps the only two hard requirements are ASDF compatibility and a free (ex: Public Domain, MIT, BSD or similar) license. It's also strongly recommended to supply at least :author (ex: :author "Full Name or Nickname <email@address.tld>"), :license and :description options in the ASDF system.

The following invocation would attempt to download and install a library named "foo" from/with Quicklisp (note that the Quicklisp and ASDF system names for a project might differ):

(ql:quickload "foo")

It's of course necessary to install Quicklisp and load it in your Common Lisp environment, first. Fortunately, this is very easy to do.

Another thing: you might need to invoke (ql:update-dist "quicklisp") before ql:quickload to ensure you get the latest quicklisp version of libraries. A new Quicklisp dist is typically released (very) approximately once a month, at which point it's a good idea to run the ql:update-dist. In the unlikely event that the dist upgrade causes problems for you, it's always possible to go back in dist time.

If you tried to ql:quickload a library but did not ql:update-dist since a library was included in Quicklisp, then Quicklisp would report that the library was not found.

A related command is (ql:update-client). New versions of the Quicklisp client (the "core" of Quicklisp that downloads dists and releases) are released infrequently.